JP2008248958A - Bearing unit for supporting wheel - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a bearing unit for supporting a wheel having long life and high rigidity and reduced in size and weight while having excellent sealing performance. <P>SOLUTION: This bearing unit X for supporting a bearing comprises a stationary ring 40, a rotating ring 42, a plurality of rolling elements 44, and a sealing device 46. The sealing device comprises a core 50 having a cylindrical fixed part 52 and a disk part 54 extending continuously with the fixed part, and a seal 60 connected to the core. A plurality of lips 60 in slidable contact with the rotating ring are formed on the seal. The core is so formed that the extension end part 54t of the disk part faces the rotating ring at a predetermined interval with the fixed part brought into contact with the outer peripheral surface 40g of the stationary ring and the disk part brought into contact and fixed to the wheel component side end surface 40c of the stationary ring. The seal is so formed that the lip 621 in slidable contact with the rotating ring on the outermost side extends to the outer side of the bearing unit and the lip 661 in slidable contact with the rotating ring on the innermost side extends to the inner side of the bearing unit. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a wheel support bearing unit that rotatably supports a wheel of an automobile or a railway vehicle with respect to a vehicle body, and in particular, an improved sealing structure, longer life, and higher rigidity of the wheel support bearing unit. Further, it relates to miniaturization and weight reduction.

Conventionally, various hub unit bearings (wheel support bearing units (hereinafter simply referred to as bearing units)) for supporting wheels of various vehicles such as automobiles and railway vehicles are known.
For example, Patent Document 1 discloses a hub unit bearing for rotatably supporting a wheel of an automobile as an example of the configuration of such a bearing unit. The hub unit bearing (hereinafter referred to as a bearing unit A) is disclosed. 2) is illustrated in FIG.

  As shown in FIG. 2A, the bearing unit A includes a stationary wheel 2 fixed to a vehicle body (a knuckle (not shown) of a suspension device) and a wheel (disk wheel (not shown)). And a rotating wheel 4 that rotates together with the disk wheel. Further, in the bearing unit A, a plurality of rolling elements (balls) 20 roll between the double row (two rows) raceway grooves 6 and 8 formed on the stationary wheel 2 and the rotating wheel 4 respectively. Embedded as possible. In this case, the rolling elements (balls) 20 roll between the raceway grooves 6 and 8 in a state where the rolling elements (balls) 20 are rotatably held one by one in a pocket formed in the annular retainer 22.

  In this case, the stationary wheel 2 is integrally formed with a fixing flange 2f that protrudes outward (in the direction of increasing the diameter) from the outer peripheral surface thereof, and is fixed to a fixing hole 2h that passes through the fixing flange 2f. By inserting a bolt (not shown) and fastening it to the vehicle body side, the stationary wheel 2 can be fixed to a knuckle of a suspension device (suspension) not shown.

  On the other hand, the rotating wheel 4 is provided with a hub 10 having a substantially cylindrical shape, and the hub 10 is fixed to a disc wheel (not shown) of a wheel via a brake rotor (not shown) of a brake. It is configured to rotate with the disc wheel. The hub 10 is fixed with a brake rotor and a disc wheel on one side (wheel side (left side in FIG. 2), hereinafter referred to as outboard side) in the axial direction (left and right direction in FIG. 2A). A hub flange 10f for external fitting is continuously provided along the circumferential direction.

  In this case, the hub flange 10f extends outward (in the diameter-enlarging direction of the hub 10) beyond the stationary ring 2, and a plurality of through-holes (in the circumferential direction) are provided in the vicinity of the extended edge. Bolt hole) 10h is provided. A brake rotor and a disc wheel (not shown) are each provided with a plurality of through holes (as an example, the same number as the bolt holes 10h) that can communicate with the bolt holes 10h. Then, the brake rotor and the disc wheel can be positioned and fixed with respect to the hub flange 10f by inserting the hub bolt 10b from the bolt hole 10h into the through hole and fastening (fastening) with a hub nut (not shown). it can.

Further, an annular inner ring structural body 12 is fitted on the hub 10 on the other side (the inner side of the vehicle body (the right side in the figure), hereinafter referred to as the inboard side) in the axial direction (the left-right direction in FIG. For example, in a state where a plurality of rolling elements 20 are held by a cage 22 between the stationary wheel 2 and the rotating wheel 4, the inner ring constituting body 12 is moved to the step formed on the hub 10. After the outer fitting, the inner ring constituting body 12 can be fixed to the inboard side of the hub 10 by crimping the inboard side end portion (the right end in the figure) of the hub 10, and the bearing unit A (more Specifically, a predetermined preload can be applied to the rolling elements (balls) 20). Here, the inner ring constituting body 12 is a member in which a raceway groove 8 facing the raceway groove 6 on the inboard side of the stationary wheel 2 is formed, and which constitutes the rotating wheel 4 together with the hub 10.
Instead of the above-described caulking and fixing, for example, after the inner ring constituting body 12 is externally fitted to the step formed on the hub 10, the inner ring is tightened by a fastening member such as a nut from the inboard side. In some cases, the structure 12 is fixed to the inboard side of the hub 10.

  In this state, the rolling elements (balls) 20 in the double row (two rows) can roll while being in contact with the raceway grooves 6 and 8 of the stationary wheel 2 and the rotating wheel 4 at a predetermined contact angle with each other. Built in. In this case, an action line (not shown) connecting the two contact points is orthogonal to each raceway groove 6 and 8 and passes through the center of each rolling element 20, and one point (action point) on the center line of the bearing unit A. Cross at. That is, the bearing unit A is configured as a rear combination type (DB) bearing.

  In addition, during driving | running | working of a motor vehicle, various loads (a radial load, an axial load, a moment load, etc.) act with respect to the bearing unit A from a wheel via the disc wheel (not shown) fixed to the hub flange 10f. . However, since the bearing unit A has a back-to-back (DB) bearing structure as described above, these various loads can be applied and high rigidity can be maintained.

  By the way, the bearing unit A is provided with various sealing devices for shielding the inside of the unit from the outside and keeping the sealed state (airtight state and liquid-tight state). In addition to preventing foreign matter (e.g., muddy water, dust, etc.) from entering the bearing unit from the outside, lubricant (e.g., grease, lubricating oil, etc.) enclosed inside leaks to the outside. Is preventing.

  In the configuration shown in FIG. 2A, a disc-like cover member (hereinafter referred to as an inboard cap) 26 is provided on the inboard side of the bearing unit A, whereas a seal member is provided on the outboard side. (Hereinafter referred to as an “outboard seal”) 24 is provided, and by providing the inboard cap 26 and the outboard seal 24, the hermeticity (air tightness and liquid tightness) inside the unit is maintained.

  In this case, as shown in FIG. 2B, the outboard seal 24 is made of various elastic materials (for example, resin such as rubber and plastic) on a part of an annular cored bar 24a formed by pressing a steel plate or the like. A seal 24b made of a material is connected, and a plurality of (for example, three) lips 24c are provided on the seal 24b. The outboard seal 24 is attached to the end portion on the outboard side of the surface facing the rotating wheel 4 (specifically, the hub 10) of the stationary wheel 2, and the lip 24c of the seal portion 24b is a hub flange. The base portion of 10f and the shoulder portion (hereinafter referred to as the groove shoulder portion) 8s of the track groove 8 on the outboard side of the hub 10 are positioned so as to slide.

Here, the bearing unit can achieve high rigidity by adopting a back-to-back combination (DB) bearing structure as described above. However, when such a DB-type bearing structure is employed, a rolling element array is provided. As the distance between the tracks (distance between the track trains) is set larger (wider), it is easier to obtain a structure with increased rigidity, and it is easier to extend the service life.
On the other hand, for example, in the bearing unit for the front wheel of a front engine front wheel drive (FF) vehicle, the size in the axial direction is limited, so there is a limit to the size increase of the bearing unit. It is not easy to increase the distance between rows. For this reason, it is desired to realize a bearing unit that has a structure in which the space between the track shoulders of the outboard side raceway groove of the hub is diverted to the space between the raceway rows and the distance between rows of the rolling elements is enlarged.

Also, if a groove shoulder is provided in the outboard side raceway groove, the weight of the hub will increase by that amount, and the bearing unit (specifically, the groove shoulder portion will be omitted in advance). , Hub) can be reduced in weight. Since the bearing unit becomes an unsprung load (unsprung weight) after being mounted on the automobile, the steering stability of the automobile can be improved if the bearing unit can be reduced in weight.
JP 2002-21858 A

  However, when the bearing unit structure is formed in which the groove shoulder of the outboard side raceway groove is omitted in advance and the inter-row distance between the rolling elements is increased, the outboard seal and the rolling elements are positioned very close to each other. The pressing force (pressing force toward the outside of the bearing unit) applied to the seal (specifically, the lip) of the outboard seal by the lubricant (for example, grease) that flows from the row of moving objects to the outboard side It gets bigger. Depending on the magnitude of the pressing force, the lip may be separated from the rotating wheel, and the grease may leak to the outside of the bearing unit. As described above, the brake rotor (not shown) of the brake is fixed to the hub flange of the bearing unit.If the leaked grease adheres to the brake rotor, the braking force of the brake is deteriorated. Need to be surely prevented.

  The present invention has been made to solve such a problem, and the object thereof is a wheel capable of extending the life and rigidity, as well as reducing the size and weight while having excellent sealing performance. The object is to provide a bearing unit for support.

  In order to achieve such an object, a wheel support bearing unit according to the present invention includes a stationary wheel fixed to a vehicle body constituent member, a rotating wheel to which the wheel constituent member is fixed and rotates together with the wheel constituent member, Provided with a plurality of rolling elements formed on the stationary ring and the rotating ring, respectively, and incorporated so as to be able to roll between two opposing rows of raceway grooves, and a sealing device for keeping the inside airtight and liquid tight is doing. In such a wheel support bearing unit, the sealing device is continuous with a cylindrical fixed portion extending in a predetermined direction, and an extended end on one side of the fixed portion, and has a predetermined angle with respect to the fixed portion. And a seal connected to the core, and the seal is provided with a plurality of lips extending so as to be in sliding contact with the rotating wheel. ing. The metal core is fixed to the stationary wheel by bringing the fixed portion into contact with the outer peripheral surface of the stationary wheel and bringing the disk portion into contact with the end surface of the stationary wheel on the wheel component member side. In the state, the disc portion is configured such that the extended end portion thereof is opposed to the rotating wheel with a predetermined interval, whereas the seal bears a lip that is in sliding contact with the rotating wheel on the outermost side. The lip is configured to extend toward the outside of the unit, and the lip that is in sliding contact with the rotating wheel on the innermost side is configured to extend toward the inside of the bearing unit.

In this case, when the disk portion extends a tangent from the outer peripheral edge of the bearing unit of the raceway groove on the wheel component member side of the rotating wheel, the core is positioned and fixed so as to intersect the tangent. ing.
In that case, it is preferable that the said metal core is made into the structure where the extension edge part of the disc part was bent toward the inward of the bearing unit along the outer peripheral surface of a rotating wheel.
Note that two rows of raceway grooves are formed in the stationary wheel and the rotating wheel, respectively, and at least the groove shoulder on the arrangement side of the sealing device is previously omitted from the raceway groove on the wheel component side. Thus, a structure in which the distance between the rows of rolling elements is increased is formed.

  According to the wheel support bearing unit of the present invention, while having excellent sealing performance, the groove shoulder portion of the outboard side raceway groove is omitted, and the distance between the rows of rolling elements is increased, thereby extending the life and improving the life. Rigidity, size reduction, and weight reduction can be achieved.

  A wheel support bearing unit (hereinafter simply referred to as a bearing unit) according to the present invention will be described below with reference to the accompanying drawings. The wheel support bearing unit according to the present invention can be applied as a bearing unit that rotatably supports the wheels of various vehicles such as automobiles and railway vehicles. The case where it is applied as a hub unit bearing is assumed as an example. In this case, the basic configuration of the bearing unit according to the present invention is assumed to be the same as that of the conventional bearing unit A (FIG. 2 (a)) described above. The description is omitted or simplified, and the characteristic configuration of the present invention will be described below.

  Such a bearing unit can be used for a vehicle driven wheel (front engine rear wheel drive (FR) vehicle and rear engine rear wheel drive (RR) vehicle front wheel, front engine front wheel drive as shown in FIG. 2A). (FF) Rear wheel of a vehicle) may be configured as a hub unit bearing, or all driving wheels of an automobile (rear wheels of FR and RR vehicles, front wheels of FF vehicles and four-wheel drive (4WD) vehicles). You may comprise as a hub unit bearing which supports a ring | wheel.

1 (a) to 1 (d) show a sealing structure on one side (wheel side (left side in the figure), hereinafter referred to as outboard side) of the bearing unit X according to an embodiment of the present invention in the axial direction. It is shown.
The bearing unit X includes a stationary wheel 40 fixed to a vehicle body (a knuckle (not shown) of a suspension device) and a rotating wheel 42 fixed to a wheel (disk wheel (not shown)) and rotating together with the disk wheel. And are formed in the stationary wheel 40 and the rotating wheel 42 so as to be able to roll between the raceway grooves 40a and 42a of double rows (as an example, two rows (only the outboard side is shown)) facing each other. A plurality of rolling elements (balls) 44 and a sealing device 46 for keeping the inside airtight and liquid-tight are provided.

In this case, the rolling elements (balls) 44 roll between the raceway grooves 40a and 42a in a state in which the rolling elements (balls) 44 are rotatably held one by one in a pocket formed in the annular retainer 48. Thereby, each rolling element 44 can roll between the raceway grooves 40a and 42a without the rolling surfaces being in contact with each other. As a result, the rolling elements 44 come into contact with each other and friction is generated. It is possible to prevent an increase in rotational resistance and seizure caused by the occurrence. Note that a lubricant (for example, grease) is enclosed inside the bearing unit X in order to more effectively prevent such an increase in rotational resistance and seizure.
Here, FIG. 1A shows an example of a configuration in which a ball is applied as the rolling element 44. However, as the rolling element 44, various rollers (cylindrical rollers, tapered rollers, and spherical rollers are used instead of the balls). Etc.) may be applied.

  Further, such a bearing unit X is assumed to have a rear combination type (DB) bearing structure in the same manner as the bearing unit A (FIG. 2A), and the raceway groove on the outboard side of the stationary ring 40 is assumed. The groove shoulder portion (6s portion shown in FIG. 2B) on the side where the sealing device 46 is disposed is removed in advance from 40a and the raceway groove 42a on the outboard side of the rotating wheel 42 is disposed on the side where the sealing device 46 is disposed. The groove shoulder (8s portion shown in FIG. 2 (b)) is omitted in advance so that the inter-row distance of the rolling elements 44 is increased. As a result, only the distance between the rows of the rolling elements 44 can be increased without particularly increasing the dimension (size) in the axial direction (the left-right direction in FIG. 1A), and the rigidity of the bearing unit X can be effectively increased. Can be enhanced.

  In addition, the axial dimensions of the stationary wheel 40 and the rotating wheel 42 can be reduced by an amount corresponding to the groove shoulder, and as a result, the bearing unit X can be easily downsized. Further, the stationary wheel 40 and the rotating wheel 42 can be reduced in weight by the amount corresponding to the groove shoulder, and as a result, the bearing unit X can be easily reduced in weight.

  In the present embodiment, the sealing device (hereinafter referred to as an “outboard seal”) 46 includes an annular cored bar 50 and a seal 60 connected to the cored bar 50. In this case, the cored bar 50 is continuous with the cylindrical fixed portion 52 extending in a predetermined direction and the extending end on one side of the fixed portion 52, and extends at a predetermined angle with respect to the fixed portion 52. It is comprised by the disk part 54 to take out. On the other hand, the seal 60 is provided with a plurality of lips 60 l extending so as to be in sliding contact with the rotating wheel 42.

  As an example, in the configuration shown in FIG. 1A, the cored bar 50 has a cylindrical shape in which the fixing portion 52 extends in a predetermined direction (the left-right direction in the figure) with a predetermined length (distance in the same direction in the figure). In addition, the disk portion 54 has a predetermined length (distance in the vertical direction in the figure) at a substantially right angle with respect to the fixed portion 52, and an extension end (one figure) of the fixed portion 52. It is formed in an annular flat plate shape (ring plate shape) extending in the direction of diameter reduction (downward in the figure) continuously to the left end of FIG. That is, in this case, the core metal 50 is configured so that the longitudinal cross-sectional shape is substantially L-shaped, and is press-fitted and fixed (specifically, fitted) to the stationary wheel 40 of the bearing unit X, It is always kept stationary.

  The metal core 50 causes the fixed portion 52 to abut on the end of the outer peripheral surface 40b of the stationary wheel 40 on the outboard side, and causes the disc portion 54 to abut on the end surface 40c of the stationary wheel 40 on the outboard side. In this state, the disk portion 54 is fixed to the stationary wheel 40, and the extended end portion (the lower end portion of FIG. 1A) 54 t is connected to the rotating wheel 42 (specifically, the root of the hub flange 42 f). It is configured to face the peripheral surface 42s) of the part with a predetermined interval.

  At that time, the facing distance between the extended end portion 54t of the disc portion 54 and the peripheral surface 42s of the rotating wheel 42 is not particularly limited, but is preferably set as narrow as possible. In the present embodiment, as an example, as shown in FIG. 1B, the disc portion 54 is a peripheral portion on the outer side of the bearing unit of the raceway groove 42 a on the outboard side of the rotating wheel 42 (left side in the figure). When a tangent is extended from 42c, the cored bar 50 is positioned and fixed so as to intersect with the tangent (straight line L in the figure, hereinafter referred to as tangent L). That is, by positioning the cored bar 50 in this way, the extended end portion 54t of the disc portion 54 can be positioned closer to the peripheral surface 42s of the rotating wheel 42 than the tangent L.

Here, when the lubricant (for example, grease) sealed in the bearing unit X flows from the row of rolling elements (balls) 44 to the outboard side during the operation of the bearing unit X, the lubricant is Then, it flows (discharges) from the row of the rolling elements (balls) 44 in the direction of the tangent L.
At this time, the extended end portion 54t of the disc portion 54 is positioned closer to the peripheral surface 42s of the rotating wheel 42 than the tangential line L, so that the grease that flows (discharged) in the tangential L direction is the disc. It will hit part 54.

That is, the pressing force (specifically, the pressing force toward the outside of the bearing unit X) applied from the flowing grease can be reliably received by the disc portion 54 of the cored bar 50. Since the facing distance between the extended end portion 54t of the disc portion 54 and the peripheral surface 42s of the rotating wheel 42 is set to be very narrow, as a result, from the grease that acts on the lip 60l of the seal 60. It becomes possible to suppress the pressing force of.
Thereby, the fluctuation | variation of the sliding contact state of the lip 60l with respect to the rotating wheel 42 (circumferential surface 42s) is suppressed, and the sealing performance of the outboard seal 46 can always be kept constant. As a result, the inside of the bearing unit X can be shielded from the outside for a long period of time and kept in a sealed state (airtight state and liquid-tight state).

  As shown in FIG. 1C, the cored bar 50 has an extended end portion 54t of the disc portion 54 that is an outer peripheral surface of the rotating wheel 42 (specifically, a peripheral surface 42s of the root portion of the hub flange 42f). It is more preferable that the structure bends toward the inside of the bearing unit X (to the right in the figure) along the). By forming the extended end portion 54t of the disc portion 54 in such a bent structure, the grease that has flowed (discharged) in the tangential L direction and collided with the disc portion 54 is bent in the extended end portion 54t. Guide along the direction.

  That is, the grease that collides with the disk portion 54 is guided along the bending direction of the extended end portion 54t to change the flow direction thereof, and travels along the disk portion 54 from the extended end portion 54t to the stationary wheel 40. It flows in the direction (upward direction in FIGS. 1A and 1C). The grease that has flowed in the direction of the stationary wheel 40 collides with the facing surface 40 s of the stationary wheel 40 with respect to the peripheral surface 42 s of the rotating wheel 42, and travels along the surface of the facing surface 40 s and further the rolling element (ball) 44. It flows between rows of moving bodies (balls) 44. As a result, the grease is circulated inside the bearing unit X.

  In this way, the extended end portion 54t of the disc portion 54 has a bent structure, so that the grease flowing (discharged) in the direction of the tangent L from the row of rolling elements (balls) 44 is actively circulated ( Can make a circulating flow of grease). For this reason, it is possible to suppress the pressing force from the grease that acts on the disk portion 54 of the cored bar 50. As a result, the pressing force from the grease that acts on the lip 60l of the seal 60 is further reduced. It becomes possible to suppress it reliably. Thereby, the sealing performance of the outboard seal 46 can be remarkably enhanced, and the bearing unit X can have a very excellent sealing structure.

In the configuration shown in FIG. 1C, the extended end portion 54t of the disc portion 54 extends along the outer peripheral surface of the rotating wheel 42 (specifically, the peripheral surface 42s of the root portion of the hub flange 42f). Although the bearing unit X is bent toward the inner side (right side in the figure), the bent structure of the extended end portion 54t is not limited to such a bent structure. For example, as shown in FIG. 1D, the extended end 54t of the disc portion 54 is inclined flatly toward the inside of the bearing unit X along the peripheral surface 42s of the rotating wheel 42. It is good also as a structure.
Further, as in the configuration shown in FIG. 1 (e), the end portion (right end in the figure) of the fixed portion 52 opposite to the continuous side of the disc portion 54 is located outside the bearing unit X (upper side in the figure). ) And then folded back to the outboard side, and the tip 52t may be opposed to the hub flange 42f with a very small gap (that is, a labyrinth structure). By forming such a labyrinth La, the muddy water resistance of the outboard seal 46 can be further improved.

  Here, the size (extension length, thickness (distance in the vertical direction in FIG. 1 (a)) and diameter, etc.) and shape of the fixing portion 52, the shape, and the size (extension length) of the disc portion 54 The thickness, dimension (dimensions such as the distance in the left-right direction in the figure) and diameter), shape, and the like are arbitrarily set depending on, for example, the size and shape of the stationary wheel 40 of the bearing unit X, and thus are particularly limited. Not.

Further, the angle of inclination of the disc portion 54 with respect to the fixing portion 52 is not particularly limited, and may be arbitrarily set according to the use conditions of the outboard seal 46 and the like. Regardless of the inclination angle with respect to the fixed portion 52, the extended end portion 54t of the disc portion 54 extends along the outer peripheral surface of the rotating wheel 42 (specifically, the peripheral surface 42s of the root portion of the hub flange 42f). What is necessary is just to make it the structure bent toward the inner side (right side of Fig.1 (a)) of the bearing unit X. FIG.
Furthermore, the material and the forming method of the cored bar 50 are not particularly limited. For example, the cored bar 50 is made of a predetermined metal plate (made of a steel plate) and may be formed by pressing the metal plate (steel plate). .

  In the configuration shown in FIG. 1 (a), as an example, a stepped portion 40g formed by continuously cutting the end portion on the outboard side of the outer peripheral surface 40b over the entire circumference into a concave shape with respect to the stationary wheel 40 is provided. It has a structure in which the outboard seal 46 is assembled by fixing (fitting) the fixing portion 52 of the cored bar 50 to the stepped portion 40g.

The size (width (distance in the left-right direction in FIG. 1A) and depth (distance in the vertical direction in FIG. 1)) and shape of the stepped portion 40g are not particularly limited. What is necessary is just to set arbitrarily according to a magnitude | size, a shape, and the magnitude | size and shape of the sealing device 46 (core metal 50). As an example, in the configuration shown in FIG. 1A, the width of the stepped portion 40g is set to be slightly larger than the extended length of the fixing portion 52 of the cored bar 50 (the distance in the left-right direction in the figure). In addition, the depth is set to be slightly larger than the thickness of the fixing portion 52 (the distance in the vertical direction in the figure).
With this configuration, the entire fixing portion 52 of the cored bar 50 can be disposed with respect to the stepped portion 40g, and the fixed portion 52 of the cored bar 50 and the stepped portion 40g of the stationary ring 40 are in contact with each other. The contact area (fitting area) can be increased.

  As a result, the fitting force of the metal core 50 to the stationary wheel 40 can be increased, and the lubricant that flows from the row of rolling elements (balls) 44 to the outboard side after assembly to the bearing unit X (as an example, grease). Thus, even when a pressing force (a pressing force in the external direction of the bearing unit (the left direction in FIG. 1A)) acts on the outboard seal 46, it is possible to sufficiently counter the pressing force. Therefore, it is possible to prevent the metal core 50 from moving (that is, misaligned) in the direction outside the bearing unit X (the left direction in FIG. 1A), and the sealing performance of the outboard seal 46 is always constant. Can be kept in.

  Further, since the axial dimension (extension length) of the fixing portion 52 of the core metal 50 can be absorbed by the axial dimension of the stationary ring 40, the substantial dimension of the outboard seal 46 in the axial direction is The thickness dimension of the disc portion 54 of the cored bar 50 and the axial dimension of the seal 60 (extension length of the lip 60l (62l, 64l, 66l)) can be suppressed to the total. Therefore, the size of the bearing unit X can be reduced by adopting such a sealing structure.

  In this case, the outboard seal 46 is provided with a fitting allowance for fitting to the stationary wheel 40 with respect to the inner diameter dimension (specifically, the inner diameter dimension of the fixing portion 52 of the cored bar 50). ing. That is, the outboard seal 46 is configured by setting the inner diameter dimension of the fixing portion 52 of the cored bar 50 to be smaller than the diameter dimension of the stepped portion 40g portion of the stationary wheel 40 by the fitting allowance. . At that time, the fitting allowance to be set to the fixing portion 52 of the cored bar 50 is not particularly limited because it may be arbitrarily set according to the size of the stationary wheel 40 or the like.

  Further, in the configuration shown in FIG. 1A, a stepped portion 40g is provided in the stationary wheel 40, and the cored bar 50 (fixed portion 52) is fixed (fitted) to the stepped portion 40g, whereby the outboard seal 46 is provided. For example, the fixing portion 52 of the cored bar 50 is fixed (fitted) to the end portion on the outboard side of the outer peripheral surface 40b of the stationary wheel 40 without providing such a stepped portion 40g. In addition, a structure in which the outboard seal 46 is assembled to the stationary wheel 40 by bringing the disc portion 54 into contact with the end surface 40c on the outboard side of the stationary wheel 40 may be employed. Note that the fixing portion 52 of the cored bar 50 may be bonded and fixed to the end portion on the outboard side of the outer peripheral surface 40b of the stationary ring 40 with a predetermined adhesive or the like.

  Further, in the configuration shown in FIG. 1A, the seal 60 is connected to the cored bar 50, specifically, the outer surface of the disk portion 54 (the left side surface in the figure), and a plurality (for example, three Lip 62l, 64l, 66l is extended toward the root portion of the hub flange 42f of the rotating wheel 42, and the lip 62l, 64l, 66l is in sliding contact with the root portion of the hub flange 42f. It is made.

  In this case, the seal 60 extends the lip 62l that is in sliding contact with the outer peripheral surface 42s of the rotating wheel 42 on the outermost side (upper side in FIG. 1A) toward the outside of the bearing unit X (upward in the same figure). The lip 66l that is slidably in contact with the peripheral surface 42s of the rotating wheel 42 on the innermost side (lower side in the figure) is extended toward the inner side (downward in the figure) of the bearing unit X. It is configured as follows. Of the three lips 601 provided on the seal 60, the lip 64l positioned in the middle is, as an example, extended toward the outside of the bearing unit X (upward in FIG. 1A). It is configured. However, the lip 64l may be configured to extend toward the inside of the bearing unit X (downward in FIG. 1A).

  With such a configuration of the seal 60, foreign matters (for example, muddy water, dust, etc.) can be prevented from entering from the outside to the inside of the bearing unit X with the lips 62l and 64l, and the inside of the bearing unit X can be prevented. Leakage of lubricant (for example, grease) from the outside to the outside can be prevented by the lip 66l. Thereby, the seal 60 can effectively shield the inside of the bearing unit X from the outside, and can always keep the inside of the unit in a sealed state (airtight state and liquid-tight state).

  As the material of the seal 60, various elastic materials (for example, resin materials such as rubber and plastic) may be arbitrarily selected and applied according to the material of the core metal 50 and the like. Further, the number and shape of the lips 60l provided on the seal 60 are not limited to the configuration shown in FIG. 1A. For example, two lips 60l may be provided on the seal 60, or four or more lips may be provided. The lip 60l may be provided. Further, the connection between the core metal 50 and the seal 60 (various elastic materials) may be performed by arbitrarily selecting various methods such as adhesion, caulking, coating, and injection molding. In the present embodiment, an example is given. Assuming that the metal core 50 and the seal 60 (various elastic materials) are connected by vulcanization molding.

As described above, according to the wheel supporting bearing unit (bearing unit X) according to the present invention, it is possible to provide a structure in which the groove shoulders of the outboard side raceway grooves 40a and 42a are omitted while providing excellent sealing performance. . Thereby, the distance between the rows of the rolling elements (balls) 44 can be increased without particularly increasing the size of the bearing unit X (particularly the dimension in the axial direction). Furthermore, the axial dimension of the bearing unit X itself can be reduced.
As a result, it is possible to easily extend the life and rigidity of the bearing unit X, as well as to reduce the size and weight.

It is a figure which shows the structural example of the bearing unit for wheel support which concerns on one Embodiment of this invention, Comprising: (a) is principal part sectional drawing for demonstrating the sealing structure of the state which assembled | attached the outboard seal, (b) ) Is a conceptual cross-sectional view for explaining the arrangement position of the metal core, (c) is a cross-sectional view showing the configuration of the metal core having a curved structure at the extended end of the disk part, and (d) Sectional drawing which shows the structure of the metal core which made the extension end part of the disc part the inclination structure, (e) shows the structure of the metal core which formed the labyrinth between the fixed part and the rotating wheel (hub flange) Sectional drawing. It is a figure for demonstrating the sealing structure of the conventional wheel support bearing unit, (a) is sectional drawing which shows the example of whole structure of a bearing unit, (b) is the sealing of the state which assembled | attached the outboard seal. Sectional drawing for demonstrating the structure for the principal part.

Explanation of symbols

40 stationary wheel 40g step portion 42 rotating wheel 44 rolling element 46 sealing device (outboard seal)
50 cored bar 52 fixed part 54 disc part 54t extended end part 60 seal 60l (62l, 64l, 66l) lip X bearing unit for wheel support

Claims (4)

A stationary wheel fixed to the vehicle body component member, a rotating wheel to which the wheel component member is fixed and rotating together with the wheel component member, and a double row raceway groove formed on the stationary wheel and the rotating wheel and facing each other A wheel support bearing unit comprising a plurality of rolling elements incorporated so as to be able to roll between and a sealing device for keeping the inside airtight and liquid-tight,
The sealing device includes a cylindrical fixing portion extending in a predetermined direction, and a disc portion that is continuous with the extending end on one side of the fixing portion and extends at a predetermined angle with respect to the fixing portion. An annular cored bar and a seal connected to the cored bar, the seal is provided with a plurality of lips extending so as to be in sliding contact with the rotating wheel,
The cored bar is fixed to the stationary wheel by bringing the fixed portion into contact with the outer peripheral surface of the stationary wheel and bringing the disk portion into contact with the end surface of the stationary wheel on the wheel component member side. The disc portion is configured such that the extended end portion thereof is opposed to the rotating wheel at a predetermined interval, whereas the seal has a lip that is slidably contacted with the rotating wheel on the outermost side of the bearing unit. A wheel characterized in that it is configured to extend outward and a lip that is in sliding contact with the rotating wheel on the innermost side is configured to extend inward of the bearing unit. Supporting bearing unit.   The core metal is positioned and fixed so as to intersect the tangent line when the tangent line extends from the outer peripheral edge of the bearing unit of the raceway groove on the wheel component side of the rotating wheel. The wheel support bearing unit according to claim 1.   The said metal core has comprised the structure where the extension end part of the disc part was bent toward the inward of the bearing unit along the outer peripheral surface of a rotating wheel. Wheel support bearing unit.   Two rows of raceway grooves are formed on the stationary wheel and the rotary wheel, respectively, and at least the groove shoulder on the arrangement side of the sealing member is omitted in advance from the raceway groove on the wheel component side. The wheel support bearing unit according to any one of claims 1 to 3, wherein a structure in which a distance between rows of rolling elements is enlarged is formed.

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